Sit-up bathtub



FIG. 1 is a front prospective view of a sit-up bathtub showing our new design.

FIG. 2 is a top plane view thereof.

FIG. 3 is a cross-sectional view taken on line 3--3 of FIG. 2.

FIG. 4 is a cross-sectional view taken on line 4--4 of FIG. 2. 

The ornamental design for a sit-up bathtub, as shown. 